Fix the errors reported by NullAway

[ikhoon]

Motivation:

Before adopting NullAway(#1680) or other static analysis tools.
Manually run it and clean up errors.

Modifications:

• Fix all true positives reported by NullAway

Result:

Less NullAway errors

[anuraaga]

Looks like the majority are not inheriting the annotation from a base. Behavior for this doesn't seem well defined.

I'm curious how others treat this, for example does Kotlin treat all these methods as non-null? If so then adding the annotation is good, if not though maybe NullAway interpreting too strictly?

[trustin]

👍

[trustin]

I'm curious how others treat this, for example does Kotlin treat all these methods as non-null? If so then adding the annotation is good, if not though maybe NullAway interpreting too strictly?

/cc Kotlin users - @gary-lo @tobias- @rfkm @okue

[ikhoon]

Kotlin also inherits @Nullable annotation.

// in Java
interface Super {
    @Nullable
    String foo();
}
interface NullableSub extends Super {
    @Override
    String foo();
}
interface NonNullSub extends Super {
    @Nonnull
    @Override
    String foo();
}

// in Kotlin
// Nullable is inherited
val a: NullableSub = ...
val fooA: String? = a.foo()

val b: NonNullSub = ...
val fooB: String = b.foo()

[ikhoon]

Kotlin treats non-null by default if it does not have @Nullable.

// in Java
class Foo {
    @Nullable
    String bar() { ... }
    String baz() { ... }
}

// in Kotlin
val foo = Foo()
val bar: String? = foo.bar()
val baz: String = foo.baz()

[tobias-]

We've had issues with the Kotlin compiler in IntelliJ and the one used for Gradle exhibiting different behaviours on nonnull. Rule of thumb is that if the Gradle one accepts it, the IntelliJ one does as well. IntelliJ is more likely to accept DefaultNullable and thus causing discrepancies between the two compilations.

I will check in an hour or so.

Only read this on my phone. What @ikhoon said

[trustin]

Thanks a lot, @ikhoon 😄

[trustin]

Oh, it seems like we are getting assertion errors during the build. Perhaps the new asserts we added is the problem? 😅

[ikhoon]

Oh, it seems like we are getting assertion errors during the build. Perhaps the new asserts we added is the problem? 😅

Oops...

[codecov]

Codecov Report

Merging #2776 into master will increase coverage by 0.08%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master    #2776      +/-   ##
============================================
+ Coverage     72.78%   72.87%   +0.08%     
- Complexity    11845    11878      +33     
============================================
  Files          1042     1042              
  Lines         46090    46159      +69     
  Branches       5748     5764      +16     
============================================
+ Hits          33546    33637      +91     
+ Misses         9603     9571      -32     
- Partials       2941     2951      +10     

Impacted Files	Coverage Δ	Complexity Δ
...corp/armeria/client/RefreshingAddressResolver.java	76.35% <0.00%> (-0.68%)	20.00 <0.00> (-1.00)
...in/java/com/linecorp/armeria/common/MediaType.java	97.29% <ø> (ø)	96.00 <0.00> (ø)
...eria/internal/common/DefaultTimeoutController.java	86.17% <ø> (ø)	31.00 <0.00> (ø)
...ria/internal/common/util/ObjectCollectingUtil.java	93.33% <ø> (ø)	6.00 <0.00> (ø)
...ria/internal/server/annotation/AnnotationUtil.java	86.86% <ø> (-3.65%)	50.00 <0.00> (-2.00)
...a/com/linecorp/armeria/server/docs/DocService.java	94.21% <ø> (ø)	41.00 <0.00> (ø)
...necorp/armeria/internal/common/brave/SpanTags.java	66.66% <0.00%> (-33.34%)	3.00% <0.00%> (-2.00%)
...n/java/com/linecorp/armeria/server/HttpServer.java	40.00% <0.00%> (-20.00%)	2.00% <0.00%> (-1.00%)
...com/linecorp/armeria/client/brave/BraveClient.java	80.32% <0.00%> (-9.84%)	12.00% <0.00%> (-3.00%)
...rmeria/internal/common/brave/TraceContextUtil.java	95.83% <0.00%> (-4.17%)	5.00% <0.00%> (ø%)
... and 42 more

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[minwoox]

Thanks!